Evangelism is the sharing of the good news of Jesus Christ with the intent of inviting the person you are speaking with to trust Christ. Evangelism isn't about the results obtained or the methods used, it is about getting out there and honoring God by doing what he has told us to do. In spiritual matters you cannot keep score, measure results and even the timing of your activity as you would with temporal matters. That is not how it works, that is not how God works. Here is how it works: 1) God tells you what to do and 2) you do it. Maybe you scratch and whine, stomp your feet a bit. Maybe you try to run and hide. Or hold your breath. It will not work. God can hold His breath longer than you. God can hold your breath longer than you can too. He calls that death.
On a given day, you may do no more that scatter seeds: planting a thought in someone's mind, a thought that someone else may encourage down the line. Someone else may water a seed you planted until God chooses to germinate it. You may prick a conscience to get someone taking a slightly different approach to their life; a little change that, like turning an oil tanker, leads to a huge change in direction.
Or you may be the final push in a series a person needs to get them to trust Christ. The first push is as important as the last, because you cannot get to the end if you do not start.
You may never know the eternal impact you have on another person's life; just by scattering some seeds in their path. God is OK with that result; it is how He designed it to work at times. (How's that for intelligent design?)
I went out the other day and began intentionally scattering seed in downtown Dallas in the middle of the morning. No visible results, just scattering seeds. I never would have seen this coming a few years ago. But it was joyous to be able to honor God by being obedient. It was much easier than I expected when I acknowledged to God and myself it was about Him, and not me. I was calm, confident, unconcerned with keeping score. I pray that continues, each and every opportunity I have.